In terms of refrigerant migration, which type of compressor requires special attention during shutdown?

In the context of refrigerant migration, the rotary compressor requires special attention during shutdown because it is particularly susceptible to oil-refrigerant mixing. When a system is turned off, especially in low ambient temperatures, refrigerants can migrate from the evaporator to the compressor. This migration can lead to the accumulation of uncompressed refrigerant within the compressor, which can cause issues when the system starts up again, such as liquid slugging that can damage the compressor.

Rotary compressors often have a design that can facilitate the movement of refrigerant, thus making it important to ensure that during the shutdown process, steps are taken to minimize the potential for refrigerant and oil migration. Ensuring proper operation parameters and potentially using crankcase heaters can help prevent issues related to refrigerant migration in these systems.

The other compressor types, while they may also face issues related to refrigerant migration, are generally less sensitive to this issue than rotary compressors, making it crucial for technicians to pay special attention to rotary compressors during shutdown procedures.